Has lightning reduction function the large-sized crane

摘要

PROBLEM TO BE SOLVED: To provide a large-sized crane having an electric shock reducing function of a simple structure capable of permanently and effectively reducing electric shock by high frequency high voltage generated by resonating broadcasting radio waves. ;SOLUTION: Because an electric shock reducing device 13 has wire suspended from the vicinity of a tip on one end side of a crane movable beam 6b into the sea in a vertical direction, an impedance varying part 15 interposed serially on the halfway of wire 14 (a coil and a condenser are serially connected) and an electrode plate 17 provided in a state that the plate 17 is buried into the sea at a lower tip part of wire 14, a resonance frequency of a container crane 1 for broadcasting radio waves is changed by the impedance varying part 15 and also a sharpness degree Q becomes small, high frequency voltage induced by broadcasting radio waves becomes lower. Therefore, electric shock due to high frequency voltage acting on a lifting sling member 11 by resonance with broadcasting radio waves can be surely reduced.;COPYRIGHT: (C)2000,JPO